deepseek-ai/deepseek-harness · error · Error

seed request/header at index ${index} lacks provider/model

Error message

seed request/header at index ${index} lacks provider/model

What it means

Error "seed request/header at index ${index} lacks provider/model" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/index.ts:264

    case 'tool/result':
      assertCurrentLlmShape(event, index)
      break
  }
}

/** Reject obsolete request headers and malformed messages at the seed/load boundary. */
function assertCurrentLlmShape(event: Record<string, unknown>, index: number): void {
  const data = event['data']
  const record = typeof data === 'object' && data !== null
    ? data as Record<string, unknown>
    : undefined
  if (event['type'] === 'request/header') {
    const header = record?.['header']
    const headerRecord = typeof header === 'object' && header !== null && !Array.isArray(header)
      ? header as Record<string, unknown>
      : undefined
    const config = headerRecord?.['config']
    if (!hasProviderModel(config)) throw new Error(`seed request/header at index ${index} lacks provider/model`)
    const configRecord = config as Record<string, unknown>
    const reasoningEffort = configRecord['reasoningEffort']
    if (reasoningEffort !== undefined
      && (typeof reasoningEffort !== 'string' || reasoningEffort.length === 0)) {
      throw new Error(`seed request/header at index ${index} has an invalid reasoningEffort`)
    }
    assertAdapterDefaults(headerRecord?.['adapterDefaults'], configRecord, index)
  }
  const type = event['type']
  if (type !== 'user/message' && type !== 'assistant/message'
    && type !== 'tool/result') return
  assertMessageEventShape(event, `seed ${type} at index ${index}`)
}

const allowedAdapterKeys = new Set(['reasoningEffort', 'maxTokens'])

/** Validate adapter-default markers imported from a durable request header. */
function assertAdapterDefaults(

View on GitHub (pinned to b150a551b8)

Solutions

1. Include provider and model in the seed request header.

When it happens

Trigger: Thrown at packages/core/session/src/index.ts:264 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/cce5c43754cc5817. Report an issue: GitHub.